Choose the right kvm & kernel version

Three Components

To make it work, you need to get the right version for three components:

• Linux Module
• User Space Application
• Guest Virtio Driver

Linux Module

KVM requires a linux kernel module to support full virtualization. The linux module consists of three files: kvm.ko, kvm_intel.ko (for Intel processors), kvm_amd.ko (for AMD processors). You can install these modules just like you install drivers for your video card. The good news is, you may not need to install anything - the 2.6.20 kernel version (and higher) includes these kernel modules as part of the mainline kernel. It will depend on your distribution configuration whether these modules are actually in the distribution kernel as a built-in or provided as modules (or possibly absent). Here is a table listing the relation of KVM module versions to mainline kernel releases:

• 2.6.20 kvm-12
• 2.6.21 kvm-17
• 2.6.22 kvm-22

If you are not sure your linux distribution contain it or not, use this command:

modprobe -l | grep kvm

The linux module can be built from source code. This is also the recommended way to get the right version of linux module. Compiling from the source code, and than make install should make the linux module inserted into your /lib/modules/linux-`uname -r`. Simply make it in use by:

modprobe kvm
modprobe kvm_intel

or

modprobe kvm
modprobe kvm_amd

User space application

Compile from source code, you can get it. Otherwise, refer to the previous section.

Guest virtio driver

There was no special requirement for guest operating system if you are not using para-visualized disk ornetwork adapter. If you are using them, make sure you get virtio_pci.ko, virtio_rng.ko, virtio_blk.ko, virtio_net.ko. They are in 2.6.25 or later kernel. There is also a option to backport them.

Refer to Virtio for more information